Method of treating filament yarn



March 13, 1962 J. E. BROMLEY ETAL 3,024,517

METHOD OF TREATING FILAMENT YARN Original Filed May 18, 1959 5Sheets-Sheet 1 FIG.|.

. Q a l INVENTORS BROM LEY H. H l L LS OR N E Y March 13, 1962 J. E.BROMLEY ETAL METHOD OF TREATING FILAMENT YARN 3 Sheets-Sheet 2 OriginalFiled May 18, 1959 JMmTMtr ATTORNEY March 13, 1962 J. E. BROMLEY ETAL3,024,517

METHOD OF TREATING FILAMENT YARN Original Filed May 18, 1959 3Sheets-Sheet 3 ATTORNEY United States Patent 3,024,517 METHGD (BFTREATHNG FHLAMENT YARN James E. Bromley and William H. I-Iiils,Pensacola, Fla., assignors to The Chernstrand Corporation, Decatur,Ala., a corporation of Delaware Original application May 18, 1959, Ser.No. 813,902. Divided and this application Sept. 19, 1960, Ser. No.

6 Claims. or. 28-72 This invention relates to a method and apparatus forprocessing cold-drawable textile filaments formed from a thermoplasticpolymer. More particularly, this invention relates to a method andapparatus for continuously stretching and continuously deformingsubstantially parallel synthetic continuous textile filaments of thenylon type, whereby such filaments are rendered potentially crirnpable.

This application is a division of application Serial No. 813,902, filedMay 18, 1959.

Continuous synthetic cold-drawable filaments can be formed from nylonpolymers and the like by the wet, dry, or melt spinning processes, thelast mentioned process being employed in the commercial production ofmost, if not all, of the nylon filaments made today. The freshly formednylon filaments generally are not highly oriented and have relativelylow tensile strengths as compared to highly oriented nylon filaments inwhich the molecules are aligned or oriented in the direction of thefilament axis. To orient nylon filaments and thereby to increase greatlythe strength thereof, they may be stretched to a desired extent byattenuating them by means of thread advancing devices such as two godetsor two other thread advancing means operated at a predeterminedperipheral speed differential therebetween. In the cold-drawing ofcontinuous filaments of nylon it is' known that stretching isaccomplished advantageously when the point at which stretching occurs isfixed or localized by mechanical or thermal means. The localization ofthe stretch point is carried out ordinarily with the employment of ayarn braking device or the like located between two stretching rolldevices.

Unlike wool, synthetic filaments are relatively straight and have asmooth, slick surface, thereby not being particularly adapted forspinning into spun yarn by the conventional spinning systems. Tofacilitate the carding and/ or combing and drafting operations to whichsynthetic staple fibers are subjected in connection with spinning theminto spun yarn, it is essential to crimp them so that they will have asatisfactory contour or pattern to permit spinning thereof into spunyarn by means of conventional textile processing equipment. Numerousdevices and processes have been proposed to impart this desired crimp orcrinkle to synthetic continuous filaments. One known form of a crimpingdevice uses toothed gearing or serrated engaging wheels that are heatedand adapted to receive the straight continuous filaments and to shapesame by compressive forces into a crimped configuration.

While continuous filament yarns have the advantage of greater evennessand superior strength, they have several undesirable propertiesincluding low heat insulating values, lack of bulkiness desired for someend uses, and low covering power. Many attempts have been made in thepast to impart some of these desirable properties of spun yarn tocontinuous filament yarn. In addition to the fact that the expense ofmanufacturing the yarn is increased considerably, there areunfortunately certain well recognized disadvantages associatedwith theprior devices and methods for imparting bulk to continuous filamentyarn.

An object of this invention therefore is to provide a simple, rapid, andeconomical method for commercially producing a thermoplastic continuousmultiiilament or monofilament yarn having a flufiy, stretchablecharacter and possessing many properties associated with spun yarn whileretaining many properties associated with filament yarn such as strengthand freedom from pilling. Another object .of this invention is toprovide a continuous method for drawing and deforming nylon filaments ina single operation so as to render same potentially highly crimpable.Still another object of this invention is to provide a method forsimultaneously deforming and cooling nylon filaments immediately aftersaid filaments are oriented by a drawing operation. A further object ofthis invention is to provide a method for producing oriented nylonfilaments having potential crimpability. A still further object of thisinvention is to provide an improved stretching and deforming apparatusfor processing nylon or the like. A yet further object of this inventionis to provide an apparatus for processing colddrawable syntheticfilaments with which unstretched or unoriented continuous filaments arefed by a power driven feed roller through a heat-stretch zone whereinthe fila ments are heated and stretched and from which the filaments arefed between positively driven intermeshing toothed wheel members, theteeth of which are in closely spaced adjustment, and a desired number oftimes around one of said members in such a manner to provide reducedtensioning with each wrap and a separator bar or roller in spacedrelationship therewith and axially askew with respect to the axes ofsaid members.

Other objects and advantages of the present invention will becomeapparent from a study of the following specification, claims, anddrawing. Preferred embodiments of the apparatus of this invention willnow be described with reference to the accompanying drawing wherein:

FIGURE 1 is a schematic view in perspective with principal parts inlocation illustrating one arrangement of apparatus suitable forpreparing the potentially crimpable thermoplastic filaments of thisinvention;

FIGURE 2 is a fragmental view on a larger scale in perspective .partlyin axial section illustrating with more particularity the yarn heatingdevice of the apparatus herein disclosed;

FIGURE 3 is a detailed fragmental plan view illustrating an organizationof two tapered crimping toothed wheel members and a fixed spacer bar, aswell as two externally contacting spur gears operatively associated withsaid members to drive same; 7

FIGURE 4 is an elevational view in section illustrating the teeth of thewheel members in closely spaced engage: ment and the teeth of the spurgears in working contact; and

FIGURE 5 is a schematic view in front elevation with principal parts inlocation illustrating another arrangement of apparatus of the presentinvention with which the stretched and deformed filaments can besubjected to an additional heat treatment while relaxed to develop thepotential crimpability therein.

In these various figures the same reference numerals designate likeparts.

In accordance with this invention there is provided an improvedstretching and deformingmachine for processing nylon or like syntheticcontinuous filament yarn, the machine being constructed for highlyefficient and economical operation. This is made ,possible by the novelconstruction and arrangement of a feed roll assembly and a set ofdrawing and deforming toothed wheel members, together with means forheating the yarn such as a heated draw or stretch pin, a heated plate, aheated tube, and the like interposed between the said roll assembly andsaid members. From a suitable source the yarn is fed to the said feedroll assembly after being passed around or through a suitable tensioningdevice. At least one of the rolls is positively driven. The objectivesof the roll assembly are the provision of a supply of yarn at apredetermined rate and the provision that the yarn will not sliptherethrough or therearound due to the stretch tension subsequentlyapplied. In the yarn path forward with respect to the roll assembly andthe heating means there are disposed a pair of toothed wheel membersdriven in unison and intermeshing in close relationship without comingin contact with each other. At least one of said members is positivelydriven at a predetermined increased speed relative to the delivery speedof the roll assembly such that a stretch is imparted to the yarn betweenthe said roll assembly and said members. The yarn normally advancing inthe heat-stretch zone defined by the roll assembly and the members andin which the yarn heating means is disposed ordinarily contacts thesurface of said heating means to heat the yarn as desired withstretching of the filaments occurring continuously between the rollassembly and the members, including when the filaments are in contactwith the yarn heating means where most of the attenuation of thefilaments is localized. The yarn is directed in operation between saidmembers and preferably around part of the periphery of one of themembers and thence around part of the periphery of a spaced apart rolleror separator bar for a desired number of times with the yarn taking apath that is progressively longitudinally forward with respect to thepoint where said yarn initially is passed between the toothed wheelmembers. By proper spacing of the roller or separator relative to thewheel members, the yarn is intermittently engaged and disengaged betweenthe members either in a random or definite pattern. The members not onlyserve to deform the filaments of the yarn but also function to coolrapidly or to quench and thereby to harden them as they passtherebetween. Hence, the members are made preferably of heat conductivematerial. After being stretched and deformed in such manner, the yarn istaken up by suitable means in an orderly form. In accordance with anadded feature of this invention the yarn after being stretched anddeformed by the toothed wheel members but before collection thereof issubjected to an elevated temperature while little or no tension todevelop substantially the potential or latent crimp formed therein bythe preceding treatment. In such an arrangement nylon yarn may bestretched at a draw ratio between 1.0 to 1.1 and 1.0 to 6.0 and deformedin accordance with the present invention without difiiculty at filamentthrough-put speeds up to and above 1000 yards per min ute.

In the continuous filament yarn treating apparatus shown schematicallyin FIGURE 1 to which reference is made now in particular thethermoplastic cold-drawable yarn indicated by numeral 10, such as nylonand the like and composed of a bundle of smooth substantially parallelfilaments that have not been fully oriented is supplied from a yarnsource. Since the yarn is not completely oriented, it is necessary toextend the yarn to be process in order to obtain the optimum degree ofmolecular orientation therein. The yarn source can be, for example, yarnpackage 11 previously doffed from a conventional spinning machine. Whilethe invention will be described primarily in connection with anapparatus which employs a yarn package so-dofied, it is to be borne inmind that this is merely for the purpose of convenient illustration andin no sense of limitation since apparatus in accordance with the presentinvention likewise may be employed readily for processing continuousyarn which has not been doffed previously from a spinning machine.

In operation, as shown, yarn is passed over and around one end of bobbin12 or other yarn holder, such as a pirn or cone holding a yarn source.The yarn 10 is threaded conventionally around snubbing bar 13 whichfunctions as a simple, uncomplex tensioning device to assist inmaintaining an orderly and uniform supply of yarn. It will be perceivedreadily that other tensioning devices such as the gate type can be usedinstead of the tensioning device shown or that the need of a tensioningdevice may be eliminated entirely. From the tensioning device or bar 13the yarn 10 is passed through a yarn guide 14, if needed, and then to arotatably arranged thread advancing means 15 that withdraws the yarnfrom bobbin 12 and supplies same at a controlled supply rate and that isoperated at a first delivery speed. As shown, means 15 comprises a pairof suitably mounted feed rolls, at least one of which is positivelydriven. The rolls have parallel axes and engage each other in operationto nip sufficiently the yarn passing therethrough so that slippage orfree-flight of the yarn between the rolls is prevented.

From thread advancing means 15 the yarn 10 is led downwardly and aroundheated stretch or draw pin 16 where the majority of the attenuation ofthe yarn occurs. The pin is mounted to be stationary and axially askewwith respect to the axes of the feed rolls and has a smooth yarn contactsurface, details of the pin being shown with more particularity inFIGURE 2. After being passed around pin 16 a desired number of times,the yarn 10 is directed downwardly between rotatably mounted and axiallyparallel wheel members 17 and 18 having a plurality of uniformlycircumferentially spaced and longitudinally extending teeth 20 that meshin closely spaced adjustment, said members being spaced a short distancebelow pin 16. Members 17 and 18 are keyed to shafts 21 and 22respectively or are integral therewith. To drive said wheel members inunison there are provided external contacting spur gears 23 and 24having horizontally parallel axes, that mesh and are fixedly mounted onshafts 21 and 22. As the teeth 20 mesh, the yarn is subjected tolaterally applied strains increasing and decreasing in intensity as theyarn approaches and leaves the horizontal plane in which the axes ofsaid wheel members lie and where said teeth engage the notches definedby said teeth to the greatest extent. After being directed around partof the periphery of one of the members, the yarn is directedtangentially therefrom and then around part of the periphery of a roller25 mounted on a supporting frame for free rotation and positionedadjacent roll 17. A spacer bar fixedly mounted to a frame may be asuitably equivalent spacing means for roller 25. The yarn 10 is woundaround member 17 and roller or spacing means 25 a plurality of times asshown in FIGURE 1. The axis of said roller 25 is positioned at aslightly inclined angle with respect to the axes of members 17 and 18 soas to insure proper longitudinal distribution on and advancement alongthe peripheries of member 17 and roller 25, thus preventingsuperposition of the wraps thereon. In other words, the yarn wrappedaround said members and the horizontally spaced roller associatedtherewith assumes generally the shape of a flattened helix, theconvolutions of which are spaced apart, whereby the yarn advances alongwheel member 17 from the inboard end thereof to the outboard end thereofduring rotation of the members 17 and 18.

By correct positioning of the spacing means 25 with relation to thetoothed wheel members 17 and 18, the moving yarn is periodically engagedand disengaged between the wheels either in a random or definitepattern. Where there is random reengagement, the segments of thefilaments forming the ridges of the corrugations induced during initialdeformation do not form ordinarily the same part of the corrugationspreviously formed, whereby the distortion and deformation occurringduring the operation fortuitously are induced. It is seen further thatthe temperature at which the yarn is directed between the wheel membersprogressively diminishes as the yarn moves longitudinally forward onwheel members 17. Stated another way, where the yarn is passed aplurality of times between the toothed wheel members 17 and 18, thetemperature at which the first deformation is conducted is more elevatedthan during subsequent reengagements of the yarn between the saidwheels. Next, the yarn after forming the outermost convolution is fedvertically downwardly through yarn pigtail guide 26 or the like, ifneeded, which is suitably mounted and located below said wheel members.

The yarn is then taken up in an orderly arrangement in a conventionalmanner by a suitable form of package building apparatus. As shown inFIGURE 1, the yarn is taken up by a ring twisting assembly generallydenoted by reference number 27 which comprises a bobbin 28 adapted to berotated by driven belt 30 in a conventional manner to collect a supplyof the yarn indicated by numeral 31. The assembly further comprises aconventional vertically reciprocatable spinning ring 32 carrying a ringtraveller 33 adapted to revolve freely about the bobbin 28 as the yarnis twisted a desired amount and wound on the bobbin.

It may be desirable in accordance with an important feature of thisinvention to provide a uniform taper or bevel to at least one of thetoothed wheel members, as illustrated, while maintaining the axiallyparallel relation ship thereof for more even operation and, among otherthings, to assist in preventing possible jamming of the wheels due tobreakage of the yarn 10. Hence, when yarn breakage occurs, the yarn willtend to move outboard along said wheel instead of perhaps becomingaccumulated and entangled thereon. Where the wheel members 17 and 18 aretapered and the yarn progresses longitudinally along these members inthe converging direction, the extent to which the yarn is deformed intoa corrugated shape as it passes between the members from the normallyunbent shape will diminish with the frequency of the corrugationsremaining the same. Hence, it will be observed that as a result ofemploying tapered wheel members, the yarn is subjected to a reducedtension between each successive engagement of the yarn and the wheelmembers. When tapered, the wheel members have the shape of a truncatedcone instead of being cylindrical. It should be understood that thereduced tensioning may be attained by other means.

Reference is made now to FIGURE 2 where one form of a yarn brakingdevice or stretch pin 16 which is called sometimes a snubbing pin isshown in more detail and which is employed according to the presentinvention, said pin being non-rotatably mounted, preferably in theposition indicated in FIGURE 1. The cross-section of the pin for bestresults is preferably circular but also may be elliptical or have anyother suitable cross-sectional design. Since the yarn 1t frictionallyengages the surface of the pin as it travels therearound, the surface ofyarn contact area thereof for best results is smooth or moderatelysmooth and is made of a mechanically very resistant-towear material. Thestretch pin 16 can be made of a wide variety of wear resistant materialsincluding stainless steel, chromium plated steel, aluminum, a bondedceramic and the like. Preferably, it is made of aluminum flameplatedwith aluminum oxide or flame-plated with sintered tungsten carbide whichis extremely resistant to wear and performs efiiciently at thetemperatures employed. The stretch pin 16 is provided with heating means35 so that the yarn passed therearound is heated to a predeterminedelevated temperature. The heating of the pin can be achieved in asuitable manner, e.g., by heated fluid inside thereof or by internalelectric resistant heating which is preferred in view of its conveniencein operation. It is also contemplated within the purview of theinvention to provide a stretch pin with a high frequency heating means.As shown in FIGURE 2, stretch pin 16 is provided with an electricallyenergizable heater element 35, electrical power being supplied theretothrough conductive lines 36 having a terminal plug 37 adapted forreception in a power outlet source. The heater element may be embeddedin the pin as shown or it may be part of a removable cartridge orinsert. While there seems to be no theoretical limit for the diameter ofpin 16, it is desirable to stay within a reasonable range from apractical standpoint.

axial movement of said shafts. Members 17 and 18,

together with a pair of externally contacting spur gears 23 and 24, aremounted on shafts 21 and 22, said members being keyed fixedly thereto at42 and 43. At least one of said shafts is driven positively by asuitable drive mechanism, such as by an electric motor 44 (as shown),gearing, belts, and the like.

As can be seen in FIGURE 4, gears 23 and 24 contact during operation,but teeth 20 extending longitudinally of wheel members 17 and 18 are inclose but spaced adjustment. To be effective for the purpose of theinvention, the lateral pressure applied to the yarn 10 passing betweenmembers 17 and 18 to deform same into a corrugated shape is appliedmostly along the apices of teeth 20 and not in the grooves therebetween.This is accomplished by proper selection of the height and slope of theteeth. The amplitude of the corrugations formed in the yarn iscontrolled as a function of the height of the teeth 20, as well as theextent to which the teeth engage in the grooves. The frequency of thecorrugations, that is the number of alternate ridges and grooves formedin a given length of yarn, is of course controlled as a function of thenumber of teeth disposed along a given segment of the circumference ofthe wheel members 17 and 18.

With reference now to FIGURE 5 where one complete yarn treatinginstallation is shown, including means for developing the potential orlatent crimpability in the yarn, thermoplastic continuous filament yarn10 which is not fully oriented is withdrawn from a yarn package 11 andis passed over one end of bobbin 12 or other yarn holder. The yarn ispassed around snubbing bar 13' and through a pigtail guide 14, afterwhich it is led through a rotatably mounted feed roll assemblydesignated generally by numeral 45, said assembly comprising idler roll46 having a rubber cot and idler roll 47 associated with driven roll 48.Shaft 50 is attached at an end of roll 46 and is mounted at the otherend at point 51 for pivotal movement of roll 46 about 51. Coiled spring52 is fixed at one end with the other end being attached to shaft 50 asindicated so as to bias swingable idler 46 into frictional engagementwith roll 48. The yarn is passed helically around driven feed roll 48and idler roll 47 and then contacts heater plate 49*, the surface ofwhich is stationary and maintained at a suitable temperature by internalelectrically energizable means. The number of laps of the yarn aroundthese rolls is sufiicient to prevent slippage of the yarn through theroll assembly 45. The yarn then is passed through the toothed wheelmembers 17 and 18 which are rotated normally at a greater peripheralspeed than the peripheral speed of the driving roll 48, therebytensioning and stretching the yarn between said feed roll assembly andsaid members. The drawn yarn is passed helically about wheel 17 andseparator roll 25.

In accordance with an embodiment of the present invention, the drawn,deformed thermoplastic filament yarn is subjected to a final heattreatment in a hot aqueous medium such as steam or by dry or combinationof both in a relaxed or substantially relaxed condition. This operationas mentioned above develops the potential crimpability induced in theyarn by the prior operation and simultaneously sets the thus-developedcrimp, thereby imparting enhanced bulkiness, crimpiness, andstretchability to the yarn. As shown, the yarn is permitted to fall ontoa conveying means 53, as for example an endless driven belt. For moreefficient operation, the yarn may be layed onto such a belt in a zig-zagpattern by means of a traverse piddler (not shown). Belt 53 carrying theyarn is passed through a heating zone in cabinet 54 having a radiantheat applicator means 55, such as an array of heating lamps, thusdeveloping the crimpiness in the yarn. It is to be understood, ofcourse, that other apparatus arrangmeents can be employed for subjectingthe yarn to an elevated temperature while under little or no tension.Without being excessively tensioned the yarn is cooled. This may beaccomplished by passing the yarn without undesirable tensioning for ashort distance through the air, excessive tension being avoided becausethe developed crimpiness may be destroyed thereby. Thereafter, the yarnis taken up in an orderly manner. As illustrated, traverse guide 56 laysthe treated yarn on a bobbin 57 surface driven by roller 58 to form ayarn package 60. It will be appreciated that the speed of yarn take-upon bobbin 57 will be coordinated properly with the delivery speed of theyarn on means 53 so that undue tensioning therebetween and excessiveyarn accumulation on means 53 are prevented.

In accordance with this invention, it has been discovered that filamentyarn of a thermoplastic polymer which is not fully oriented can beadvantageously treated to render same potentially crimpable, and capableof being easily transformed in a yarn having increased elasticity orstretchability and improved bulkiness, this being accomplished in auseful, rapid, and economical method. More particularly, the method ofthis invention comprises providing a source of not fully orientedcontinuous filament yarn in the form of a monofilament or bundle offilaments having little or no twist, the filaments being nylon or thelike. The yarn is continuously passed through a stretching zone whereinthe filaments are heated to an elevated temperature, such as by passingsame around a heated stretch pin or heated plate interposed in saidzone. Immediately after leaving the stretching zone, the filaments aredeformed into a corrugated shape having alternate ridges and grooveswhile being cooled by passing between the engagements of toothed wheels,the teeth of which are fitted together in closely spaced adjustment. Thefilaments are redeformed intermittently into a corrugated shape a numberof times by being passed between said wheels a corresponding number oftimes, each subsequent redeformation occurring at a somewhat lowertemperature. Where tapered wheels are employed, the tension to which theyarn is subjected between each successive engagement of the yarn and thewheels is decreased. The yarn which is markedly potentially crimpablethereafter is collected. An additional operation whereby the crimp isdeveloped includes subjecting the yarn while relaxed to another heattreatment as above described.

The method of the present invention is applicable to a wide variety ofcontinuous filament yarns, the requirement being that the yarn is madefrom a thermoplastic fiber-forming resin and which can be extended bydrawing and then show increased molecular orientation along the filamentaxis. The yarns may be formed by known techniques from these resins,including melt extrusion, wet spinning processes, and dry spinningprocesses. As examples of fiber-forming synthetic polymers which areincluded in the thermoplastic fiber-forming resins may be mentionedpolyethylene; polypropylene; polyurethane; copolymers of vinyl acetateand vinyl chloride; the copolymers of vinylidene chloride and a minorproportion of mono-olefinic compounds copolymerizable therewith, suchas, for example, vinyl chloride; homopolymers of acrylonitrile,copolymers of acrylonitrile and a minor proportion of at least onemono-olefinic compound copolymerizable therewith and polymer blendscontaining combined acrylonitrile in a major proportion; copolymers ofvinyl chloride and acrylonitrile; linear polyesters of aromaticdicarboxylic acids and dihydric compounds, such as polyethyleneterephthalate and the polyester derived from terephthalic acid andbis-1,4-(hydroxymethyl) cyclohexane; linear polycarbonamides such as,for example, polyhexamethylene adipamide, polyhexamethylene sebacamide,polymeric monoaminomonocarboxylic acids, such as polymeric 6-aminocaproic acid; and other fiber-forming thermoplastic polymers. Mixturesof such fiber-forming synthetic polymers also can be used. The processof this invention is applicable particularly for the treatment of yarngenerically referred to as nylon, including nylon 66, nylon 4, nylon 6,nylon 610, nylon 11, and their fiberforming copolymers thereof e.g.,6/66, 6/ 610/ 66, 66/610, etc.

While the present process is suitable for treatment of yarn whosefilaments have a normal cross-section such as that produced where aspinneret having circular shaped orifices is employed during themanufacture thereof, unusual effects may be obtained by processing yarnshaving a non-circular cross-section or having an axial passage inaccordance with the present invention. For example, when yarn composedof a plurality of continuous filaments having a body section and aplurality of finned sections or legs integrally joined to said body andradially disposed upon the surface of and extending longitudinally ofthe body, such as yarn of X- or Y-shaped crosssection, is subjected tothe treatment in accordance with the instant invention, the resultingyarn has increased covering power, resiliency, and a crisp feel. Thenumber of fins may be two, three, four, or more; and yarns having thefins are prepared by conventional methods, such as by employing duringspinning a spinneret adapted to produce filaments having the desirednumber of fins or legs. It has been found that the yarn having thenoncircular cross-section and whose bulk has been enhanced by the methodand apparatus of the present invention is excellent for rugs and thelike.

Twisted yarn can be processed as well as untwisted yarn, the requirementbeing that the yarn is not fully oriented. However, it is preferred tostart with a source of yarn having zero twist or substantially no twist.Pretwisting of the yarn is generally unnecessary and for economicconsideration is preferably avoided. The denier of the thermoplasticyarn can vary considerably, as well as the denier of the individualfilaments, the ordinary deniers of commercially available yarns beingcom pletely suitable. Yarns having different compositions and denierscan be combined before being processed to produce novelty effects.

The temperature at which the yarn heating means is operated depends uponmany factors including the type of yarn, the yarn linear speed, and theconstruction thereof. The temperature of the yarn should be elevatedpreferably to a temperature below the temperature at which adjacentfilaments will stick during the process. However, the temperature shouldbe sutficient so that the yarn will be deformed or distorted by theinterrneshing of the teeth of the stretching wheels without unduefilament breakage. The temperature to which the yarn is subjected may bein the range of C. to 250 C. when nylon 66 is processed. The surfacetemperature of the yarn heating means will depend on the many factors,such as the denier of the yarn and the speed of the yarn.

By employing the above-described apparatus and process, one produces apotentially or latently crimpable yarn which can be changed easily intoa bulked, highly crimped, stretchable continuous filament yarn. Bulkrefers to the relative volume occupied by a given weight of yarn. Hence,yarn having increased bulk, such as that produced in accordance with thepresent invention, has greater covering power and warmth. Crimped refersto the fact that the filaments contain many crimps, crinkles, curls, andthe like which bend in and out in a sinuous pattern along the length ofthe filaments and which may be in one or more planes. Stretchable refersto the fact that the yarns produced in accordance with this inventionare elastic and have the ability to accept a slight longitudinallyapplied stress and thereby to become easily extended a considerablelength without permanent elongation thereof. For example, the yarn canbe elongated 10 to 100 percent or more from its untensioned or relaXedlength and immediately recover from this elongation in the nature of theso-called stretch-yarn. It is preferred for some end uses to develop thepotential crimpability of the yarn after same has been converted into atextile article. For instance, the stretched and deformed yarn prior tothe final heat treatment advantageously may be tufted into a carpetafter which the heat treatment is applied. The tufts of yarn disposed onthe face of the carpet will bulk to a notable extent, thereby impartingmore luxurious appearance to the carpet. In such a manner the potentialcrimpability in the yarn which is on the back of the carpet and in thebacking material, since it is tightly held at these points, will not bedeveloped, thereby providing an overall more economical utilization ofthe yarn. It will be noted also that the tufting operation is made moreconvenient when the crimp is subsequently developed.

The following is an example of the above-described method of treatingyarns and filaments of this invention.

Example The filaments used as a yarn source were prepared by meltspinning polyhexamethylene adipamide, the cross section of which wasY-shaped. A yarn composed of 68 of these undrawn filaments, each ofwhich had a denier of 60 and a twist of zero turns per inch, was wound(from a spinning machine) onto a bobbin for treatment.

Apparatus corresponding to that in FIGURE 1 was used to treat the yarn.The yarn was unwound for treatment from the bobbin by passing samethrough a pair of positively driven feed rolls, the rate of withdrawalbeing about 100 yards per minute. From the feed rolls the yarn was ledonto and around a stationary stretch pin one time, the yarn movementdescribing a helical path therearound. The surface temperature of thepin was maintained at 210 C. by an electric resistant heater lo catedinside the pin and controlled by a thermistor temperature sensingcontrol device. The yarn was fed between two metal toothed wheelsmeshing but not having contacting teeth. The wheels were driven inunison at a predetermined speed so that a stretch of about 400 percentoccurred in the yarn between the feed rolls and withdrawal from thesewheels. The yarn was passed through the wheels for an additional threetimes; before each pass the yarn was directed around a spaced roller.Thereupon the yarn was collected on a conventional ring twisterassembly.

A tufted carpet was produced from the yarn so treated. The carpet wassubjected to live steam at an elevated temperature of 130 0., therebydeveloping the potential crimpability therein. The resulting carpet hada flulfy, bulky appearance and possessed an aesthetic appeal.

From the foregoing it is seen that the advantages of the presentinvention are many. The method results in the production of yarns havingdesirable bulk and is broadly applicable to produce such yarns from awide range of cold-drawable filaments manufactured from thermoplasticresins. The improved device for processing continuous filaments, forexample, of the nylon type, which may be run at a high speed and highefiiciency requires little operator attention. The construction andarrangement of the device make it possible to convert at moderateexpense existing textile processing equipment such as a draw twisteradapted for nylon processing into a machine of the type disclosed andclaimed herein. By relatively simple adjustment the apparatus of thepresent invention can be adapted easily for the production of yarnhaving a low crimpability to a high crimpability. The inherentproperties of the treated yarn are such that they impart numerous anddesirable properties in woven, non-woven, and knitted fabrics. Yarnscomposed of non-circular cross-sections and processed in accordance withthe present invention have increased resiliency and 10 enhanced coveringpower eminently suitable for rugs, carpets, and the like.

The term yarn is used in the specification and in the claims asreferring to continuous multifilarnents, as well as to a continuousmonofilament.

Many different embodiments of the invention may be made withoutdeparting from the spirit and scope thereof. For example, while one yarntreating unit is illustrated in the annexed drawing, it will beappreciated readily that the apparatus of the instant invention may beprovided with a plurality of identical yarn processing units along itslength or having two banks of such points in back to back relationship.Moreover, novelty effects of various sorts may be imparted to the yarnby irregular or regular variations in the yarn speeds and stretches.Furthermore, it will be appreciated that an undrawn thermoplastic yarnmay be treated together with a drawn yarn or with a yarn which is notthermoplastic such as regenerated cellulose yarn. Therefore, it is to beunderstood that the invention is not to be limited to the specificembodiments shown and described herein, except as defined in theappended claims.

What is claimed is:

1. A method for texturing a continuous filament yarn made from athermoplastic polymer whereby potential crimpiness is imparted theretocomprising the steps of providing a source of a molecularly orientablecontinuous filament yarn made from a thermoplastic polymer, continuouslypassing said orientable yarn through a. heatstretch zone, heating theyarn in said zone to an elevated temperature and attenuating the yarn insaid zone a predetermined extent thereby to increase the molecularorientation thereof, the majority of the attenuation being 10- calizedin the area where said yarn is heated, thereafter continuously deformingthe heated and stretched yarn into a corrugated shape simultaneouslywhile same is being cooled by continuously passing the yarn between theintermeshing engagement of toothed wheels, successive portions of theyarn being subjected to forces laterally applied by the teeth of saidwheels alternately in one direction and then in the opposite directionto cause deformation of the yarn mostly along the apices of the teeth,then intermittently redeforming the yarn into a corrugated shape aplurality of times by passing same between said wheels a correspondingnumber of times, and collecting said yarn in an orderly manner.

2. A method for treating a continuous filament yarn made from a nylonpolymer whereby potential crimpiness is imparted thereto comprising thesteps of providing a source of a molecularly orientable nylon continuousfilament yarn, continuously passing said orientable yarn through aheat-stretch zone, wherein the yarn is heated to an elevated temperatureand is attenuated a predetermined extent thereby to increase themolecular orientation thereof, the majority of the attenuation beinglocalized in the area where said yarn is heated, thereafter continuouslydeforming the heated and stretched yarn into a corrugated shapesimultaneously while same is being cooled by continuously passing theyarn between the engagement of toothed wheels, then intermittentlyredeforming the yarn into a corrugated shape a plurality of times bypassing same between said wheels a corresponding number of times,reducing the tension on the yarn between each successive engagement ofthe yarn and said wheel, and collecting said yarn in an orderly manner.

3. The method as defined in claim 2 wherein said nylon filament yarn iscomposed of polyhexamethylene adipamide polymer and has a non-circularcross-section, the temperature to which said yarn is subjected in saidheatstretch zone being in the range of C. to 250 C.

4. A method for texturing a continuous filament yarn made from a nylonpolymer comprising the steps of providing a source of a molecularlyorientable nylon continuous filament yarn, continuously passing saidorientable yarn through a heat-stretch zone, heating the yarn in saidzone to an elevated temperature and attenuating the yarn in said zone apredetermined extent thereby to increase the molecular orientationthereof, the majority of the attenuation being localized in the areawhere said yarn is heated, thereafter continuously deforming the heatedand stretched yarn into a corrugated shape simultaneously while same isbeing cooled by continuously passing the yarn between the engagement oftoothed wheels, successive portions of the yarn being subjected toforces laterally applied by the teeth of said wheels alternately in onedirection and then in the opposite direction to cause deformation of theyarn mostly along the apices of the teeth, intermittently redeformingthe yarn into a corrugated shape a plurality of times by passing samebetween said wheels at predetermined intervals a corresponding number oftimes, permitting the yarn to relax, subjecting the yarn while relaxedto an elevated temperature thereby to develop the potential crimpinessinduced in the yarn and to set the thus-developed crimpiness, coolingthe yarn without excessive tensioning thereof, and then collecting saidyarn in an orderly manner.

5. A method for treating a continuous filament yarn made from a nylonpolymer comprising the steps of providing a source of a molecularlyorientable nylon continuous filament yarn, continuously passing saidorientable yarn through a heat-stretch zone, wherein the yarn is heatedto an elevated temperature and is attenuated a predetermined extentthereby to increase the molecular orientation thereof, the majority ofthe attenuation being localized in the area where said yarn is heated,thereafter continuously deforming the heated and stretched yarn into acorrugated shape simultaneously while same is being cooled bycontinuously passing the yarn between the engagement of toothed wheels,intermittently redeforming the yarn into a corrugated shape a pluralityof times by passing same between said wheels at predetermined intervalsa corresponding number of times, reducing the tension on the yarnbetween each successive engagement of the yarn and said wheels,permitting the yarn to relax, subjecting the yarn while relaxed to anelevated temperature thereby to develop the potential crimpiness inducedin the yarn and to set the thus-developed crimpiness, cooling the yarnwithout excessive tensioning thereof, and then collecting the said yarnin an orderly manner.

6. The method as defined in claim 5 wherein said nylon yarn is composedof polyhexamethylene adipamide polymer and has a non-circularcross-section, the temperature to which said yarn is subjected in saidheat-stretch zone being in the range of C. to 250 C.

References Cited in the file of this patent UNITED STATES PATENTS2,068,139 Kronheim Jan. 19, 1937 2,326,174 Rutishauser AugflO, 19432,348,182 Slayter May 2, 1944 2,385,894 Taylor Oct. 2, 1945 2,977,746Klein et a1. Apr. 4, 1961 FOREIGN PATENTS 780,755 Great Britain Aug. 7,1957

1. A METHOD FOR TEXTURING A CONTINOUS FILAMENT YARN MADE FROM ATHERMOPLASTIC POLYMER WHEREBY POTENTIAL CRIMPINESSF IS IMPARTED THERETOCOMPRTISING THE STEPS OF PROVIDING A SOURCE OF A MOLECULARLY OORIENTABLECONTINUOUS FILAMENT YARN MADE FROM A THERMOPLASTIC POLYMER, CONTINOUSLYPASSING SAID ORIENTABLE YARN THROUGH A HEATSTRETCH ZONE, HEATING THEYARN IN SAID ZONE TO AN ELEVATED TEMPERATURE AND ATTENUTATING THE YARNIN SAID ZONE A PREDETERMINED EXTENT THEREBY TO INCREASE THE MOLECULEORIENTATION THEREOF, THE MAJORITY OF THER ATTENTUATION BEING LOCALZED INTHE AREA WHERE SAID YARN IS HEATED, THEREAFTER CONTINOUSLY DEFORMING THEHEATED AND SETCHED YARN INTO A CORRUGATEDF SHAPE SIMULTANEOUSLY WHILESAME IS BEING COOLED BY CONTINOUSLY PASSIGN THE YARN BETWEEN THEINTERMESHING ENGAGEMENT OF TOOTHED WHEELS, SUCCESSIVE PORTIONS OF THEYARN BEING SUBJECTED TO FORCES LATERALLY APPLIED BY THE TEETH OF SAIDWHEELS ALTERNATELY IN ONE DIRECTION AND THEN IN THE OPPOSITE DIRECTIONTO CAUSE DEFORMATION OF THE YARN MOSTLY ALONG THE APICES OF THE TEETH,THEN INTERMITTENTLY REDEFORMING THE YARN INTO A CORRUGATEDF SHAPE APLURALITY OF TIMES BY PASSING SAME BETWEEN SAID WHEELS A CORRESPONDINGNUMBER OF TIMES, AND COLLECTING SAID YARN IN AN ORDERLY MANNER.